Odd surface phenomenon...rust? corrosion? struck-through?
rmpsrpms
Posts: 1,906 ✭✭✭✭✭
Going through some BU rolls of 1954-S Cents, I found a bunch of coins with some interesting surface phenomena, with patterns having the following characteristics:
...not random but also not identical or predictable between coins
...tend to cluster in similar areas
...incuse and shallow
...obscure normal surface details
I initially thought these could be due to some sort of die corrosion, but a rusty die produces a raised feature that is constant from strike to strike, and wears like other die features, in essence a "die variety". These patterns are incuse, and presumably don't produce the same features strike to strike. This is more like an "error". On another forum, one member stated that this occurs on Morgan Dollars, and has been explained as "struck through condensation". Apparently, in the mornings the mint machinery is cold, and warm/moist air blowing over it could cause condensation. First few strikes with the "wet" die would produce a struck-through condensation error. Is this what we're looking at here?
Here is an animation of 15 coins, all from the same die, all showing this phenomenon. Let me know your thoughts.
Comments
Post mint wear
Looks like a bunch of strike thru's have "cratered" the original surface.
I'd guess that it's struck thru grease on the die.
The left side of the coin looks like that, but the
right side in the field areas has raised areas,
which do not look like a normal struck thru area.
If you're going to the ANA, bring it, and I'll like to
see it in-hand.
As far as 'struck thru condensation', I've never heard
that term, and I don't believe it is a genuine event.
Any amount of 'condensation' would not be
in the die room, or the press room, imo, and in
any case, would be vaporized by 65-75 tons of
pressure, without leaving anything to see on the
surfaces of any coin.
Whoever used that term and description - wow.
No, not wear. These are all BU coins. Wear happens on the high points. This phenomenon is occurring in the fields (low areas).
That seems reasonable at first, but if you follow the images, the surface looks normal on coins that don't show the phenomemon in a particular location, yet show the phenomenon on other coins in that same location, and vice versa. Plus, if there were die damage, the features would be raised, not incuse.
http://macrocoins.com
I have seen rolls like this that are pick outs!
We’re they rolled in Federal Reserve Bank wrapping?
I saw the part that looked raised but dismissed it as the lighting.
OP turn the coin an post another image with the head sideways. That should settle it. neat coin.
Grease. (The goopy lubricant, not the movie).
IMO, you either have a bunch of moving crap on the die or most probable, a bunch of "contaminated" planchets are being struck!" That's my opinion and I'm sticking to it.
Note to all...this is an animation of 15 different coins from the same die.
I'd believe it was simply struck through grease, but I'm not sure why grease and water would really behave much differently. Neither is really compressible, so water on the surface of the die could be trapped similarly to grease and create pockets that could obscure design details.
http://macrocoins.com
Yes, it might be the 'animation' of the 15 coins
that make the right side stuff looked raised.
Here is an image of a single reverse from one of the 15 coins:
http://macrocoins.com
No, this was a tubed roll.
http://macrocoins.com
Great photos. I don't recall seeing that extensive look before.
I have had coins from rolls that have had a series of moving and shape shifting single blob depressions which I assumed was grease that moved between strikes. They were in the same general area on each coin and either grew or shrank a bit, but not spread across the coin like yours.
If not the "wet dies" explanation, I wonder if a thin layer of grease or oil had debris from something in it and kept shifting with each strike until it worked its way out or was wiped off the dies at some point.
"To Be Esteemed Be Useful" - 1792 Birch Cent --- "I personally think we developed language because of our deep need to complain." - Lily Tomlin
Looks like strike thru's and I want one! LOL Deciding what caused them should be difficult, Perhaps even a build up of grease between the die and collar as there is a mass at the rim.
Water would not stay in one place in significant quantity as might grease. Water would also evaporate.
JMO.
Sure, water is less viscous so would tend to be moved more easily out of between the die and planchet. As Fred Weinberg said, the striking pressure would tend to vaporize it, but grease is not immune. Put either one under sufficient pressure and they will heat up. Grease leaves a sticky residue which is even less viscous, so tends to stay in place. Water of course would "go away" quickly, which is why it is a less plausible explanation. However, the patterns moving about as shown in the images doesn't make much sense from grease perspective. Struck through grease tends to be more stable, and less (shall I say) chaotic/fractal in nature.
http://macrocoins.com
OK, let's meet in the middle - we'll attribute it to oil.
Hah! Maybe so.
http://macrocoins.com
"Mint Mice"
2 of the coins look like they have wheel marks from a coin counter.
I am talking about the 2 with a dark line
I'm in the contaminated planchet camp, that caused the anomalies seen on the struck coins. What that might have been is just a guess.
"Keep your malarkey filter in good operating order" -Walter Breen
Or maybe "copper fungus"?
3 of the coins have dark lines. Is this from a coin counter? I have seen these before but did not think much about them.
http://macrocoins.com
Well, what "could" have been on the planchets in the normal minting process?
I suppose I should ask the question: have others seen this type of surface phenomena on other coins?
Further note that while these 15 coins came from the same die, I also found from 3-20 pieces each from total of 9 different dies in the rolls I went through. It seems like someone in the distant past may have pulled (culled? collected?) these and put them together. @PTVETTER says he has seen similar pick outs. They are certainly not pretty coins, so this makes sense.
http://macrocoins.com
I would tend to support the grease theory.. and whatever dust might accumulate in the grease...Cheers, RickO
Grease is catch-all term when used in this context. When the term "struck-through grease" is used, think about all of the contaminents that can build up on the die (oils/greases of various types, metal flakes, dust, fibers, etc.)
I tend to agree, that is what this is. I've seen similar successive struck-throughs on modern coinage and the struck-through area tends to change in shape from one coin to the next. Wish I had photos to share.
Last photo shows struck thru (grease)
Consensus seems to be Struck Through Grease, which I can agree with.
http://macrocoins.com
Impacted debris filling parts of a die is very hard, tough material, although it is unstable and shifts during use. The die setter used a brass wire brush to remove this from a die before resetting it for use. If it could not be completely cleaned, the die was sent to the Engraving Dept for cleaning.
@RogerB said: "Impacted debris filling parts of a die is very hard, tough material, although it is unstable and shifts during use. The die setter used a brass wire brush to remove this from a die before resetting it for use. If it could not be completely cleaned, the die was sent to the Engraving Dept for cleaning."
However, in the case of these coins there is no evidence of die polish.
PS Any person looking at enough BU coins (especially silver from the 1950's - 1960's) will eventually come across a slightly cloudy, waxy substance with microscopic black and silver debris jammed up around the rims. It pushes off the coin or can be dissolved quickly with chemicals.
I've posted that several months ago my camera stopped linking to my computer due to updates.
Now, posting an image is very complicated and time consuming. In the past month, I have promised to post images and have forgotten what was promised. If anyone is still waiting, PM me with what you would like to see. In the meantime, I'll add an image of this grease (?) build up on the burner also. Sorry.
Die cleaning does not necessarily mean resurfacing ( aka: polishing). Debris can be removed with normal engraving tools.
I'd expect a quick wiping of the die with a towel and alcohol would do the trick. Not sure what the mint actually does, but there must be some sort of wash they do.
http://macrocoins.com
Funny, I've never seen any engraving tools next/near/far away from the coining presses. Only dirty rags and some simple hand tools.
Just being snarky and giving you a hard time. 
I'm very cranky today as I am working on a few dozen Russian medals and must translate each of them to make a label! It's so bad that I'm beginning to recognize a slew of Russian words.
When toggle presses were in use only the die setter was permitted to remove, clean in-situ, or replace a working die. He carried necessary tools for his work with him as he made the rounds of operating presses. If the brass brush did not work, then the filled die went to the Engraving Dept.
Really clogged dies went to the Department of Snarky Works for application of "Corrective Hammering."